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Effects of biodegradable plastics on isopod nutrition

2011Effects of biodegradable plastics on isopod nutrition.TIMM WOOD Camila (Brazil)
Organisation:Christian Albrechts University, Kiel (DE)Supervisor :
Summary: The use of conventional plastics has generated many environmental problems due to its improper disposal and low degradability. Large animals can get entangled in plastic parts while invertebrates have been documented to ingest micro-plastic fragments. An alternative to these environmental problems is the use of biodegradable materials from biological origin instead of petroleum-based ones. Films and small disposable products from biological sources such as starch, cellulose and bacterial metabolites have been produced and their degradability has been severely studied. Soil macro-invertebrates have been noticed to consume some of these biobased plastics, but studies usually do not go beyond notice of consumption and possible ecotoxicological effects to the organisms. As detritivores are important organisms on soil dynamics and nutrient cycling, and the ecological implications of bioplastic consumption by these organisms are not well known, this study uses the terrestrial isopod Porcellio scaber (Crustacea: Isopoda: Oniscidea) as a soil detritivore model and three biodegradable plastics to answer the following questions: 1) do isopods help biodegradable plastic mass loss in the soil. 2) do biodegradable plastics affect isopod ecology (feeding and growth rates). and 3) would isopods feed on biodegradable plastic in natural conditions? Starch-, cellulose-, and PHB-based films were used in experimental units containing soil and isopods to test their effect on bioplastic mass loss in comparison to three conventional plastics with similar presentation (and compared to animal-free controls). Another experiment tested the consumption of the three bioplastics by isopods and their feeding and growth in comparison to leaf litter in order to observe ecological effects on the animals. A third experiment was conducted simulating natural conditions with abundant soil and mixed litter to estimate potential bioplastic consumption by animals in a quasi-natural environment. These results will help to understand the consequences of disposal of these new polymers in natural environments.